This invention relates to the compounds 4-phenylthio-2-trifluoromethylmethanesulfonanilide, 4-phenylsulfinyl-2-trifluoromethylmethanesulfonanilide and 4-phenylsulfonyl-2 -trifluoromethylmethanesulfonanilide and agriculturally acceptable salts thereof. The invention also relates to herbicidal compositions containing said compounds and the use thereof to control the growth of higher plants. Methods for the preparation of the compounds are also included.
The prior art, for example, British Pat. Nos. 738,758; 854,956 and 856,452 and French Pat. No. 1,188,591 describes haloalkylsulfonamido-diphenylthioethers, diphenylsulfoxides and diphenylsulfones, some of which are substituted by trifluorormethyl groups on the phenyl rings. However, no alkylsulfonamidodiphenylthioethers, diphenylsulfoxides or diphenylsulfones are reported, nor is herbicidal activity anywhere mentioned.
Perfluoroalkylsulfonanilides substituted by phenylthio, phenylsulfinyl, and phenylsulfonyl groups are known, see for example South African Pat. No. 7,105,582. These compounds are not reported to be substituted by trifluoromethyl groups. Other publications, for example Trepka, et al., J. of Ag. and Food Chem., p. 1176 (1970) have taught that " . . . herbicidal activity was greatest with the more highly fluorinated . . . " alkylsulfonamido groups of sulfonanilides.
It was therefore very unexpected to find that the alkylsulfonanilides of the present invention showed particularly high and useful activity as herbicides.